1. Field of the Invention
The present invention relates to an information memory medium, and more particularly to an optical recording disk used for an information processing apparatus for recording, reproducing or erasing information.
2. Discussion of Background
Recently, information processing apparatus have been used for recording or reproducing image information on and from an optical recording disk as an information memory.
In the information processing apparatus of this type, the optical recording disk is mounted on a turntable and rotated so that the apparatus may perform information processing, such as recording or reproduction, on or from the optical recording disk. In order to support the optical recording disk on the turntable in the information processing apparatus, the optical recording disk is magnetically attracted by a magnetic attraction member provided on the turntable. The magnetic attraction member attracts an attractable member which is disposed on a central portion of the outside surface of the optical recording disk. In the clamp mechanism, the optical recording disk may be mounted stably on the turntable, irrespective of the thickness of the disk.
Example of the clamp mechanism of this type is disclosed in a related U.S. application, Ser. No. 004,097 filed Jan. 16, 1987, by the same assignee, now U.S. Pat. No. 4,982,399.
This related application describes an optical recording disk having the attractable member including a centering member and a magnetic member. The magnetic member is attached to the centering member by a mounting mechanism which includes retaining portions formed on the centering member and retaining claws formed on the magnetic member. Each of the retaining portions includes an aperture, large enough to allow insertion of its corresponding claw therein, an engaging projection projecting into the aperture, and the like. Each of the claws includes a vertical portion extending vertically from the magnetic member and a horizontal portion extending parallel to the magnetic member, from the extended end of the vertical portion. The claws are arranged corresponding in position to the retaining portions, so that they may engage with the retaining portions. However, in the optical recording disk of this type, since the claws must be formed in the magnetic member and engaging structure must be formed in the centering member, the centering member and the magnetic member are complicated in construction.